US10448493B2ActiveUtilityA1

Control of discharge in high voltage fluid insulation

39
Assignee: SCHLUMBERGER TECHNOLOGY CORPPriority: Apr 18, 2016Filed: Apr 18, 2016Granted: Oct 15, 2019
Est. expiryApr 18, 2036(~9.8 yrs left)· nominal 20-yr term from priority
Inventors:Christopher Todd KentSrinand KaruppoorAnthony Veneruso
H05F 3/04E21B 47/12E21B 47/00
39
PatentIndex Score
0
Cited by
11
References
20
Claims

Abstract

An instrument to produce ionizing radiation includes a high voltage source of charge and ionizing radiation; a housing filled with insulating gas and containing the high voltage source; an insulator to which the high voltage source is mounted so that the source is spaced from the housing; one or more collector electrodes arranged in the housing such that the high voltage source preferentially discharges to the collector electrode(s); a control system which determines a level of ionization of the insulating gas through the amount of discharge to the collector electrode(s); and/or discharge rate limiting means controllable by the control system to deionize the insulating fluid at a controlled discharge rate and thereby maintain the maximum rate of discharge below a predetermined current. In this way, breakdown events can be inhibited.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. An instrument for producing ionizing radiation, the instrument comprising:
 a high voltage source of charge and ionizing radiation; 
 a housing filled with insulating fluid and containing the high voltage source; 
 an insulator to which the high voltage source is mounted so that the source is spaced from the housing; 
 at least one collector electrode arranged in the housing such that the high voltage source preferentially discharges to the at least one collector electrode; 
 a control system for determining a level of ionization of the insulating fluid through an amount of discharge to the at least one collector electrode; and 
 discharge rate limiting means controllable by the control system to deionize the insulating fluid at a controlled discharge rate and thereby maintain a maximum rate of discharge below a predetermined current. 
 
     
     
       2. The instrument according to  claim 1 , wherein the discharge rate limiting means is further controllable by the control system to deionize the insulating fluid at a controlled location. 
     
     
       3. The instrument according to  claim 1 , wherein the discharge rate limiting means includes an electrical circuit which varies an electrical bias applied to the at least one collector electrode relative to the high voltage source to encourage deionization of the insulating fluid at the at least one collector electrode. 
     
     
       4. The instrument according to  claim 1 , wherein the discharge rate limiting means includes a fluid circulator which is actively controllable by the control system to circulate the insulating fluid within the housing to preferentially encourage discharge of the insulating fluid at the at least one collector electrode. 
     
     
       5. The instrument according to  claim 1 , wherein the instrument further includes a passive fluid circulator that is not under the control of the control system but which circulates the insulating fluid within the housing to preferentially encourage discharge of the insulating fluid at the at least one collector electrode. 
     
     
       6. The instrument according to  claim 1 , wherein the at least one collector electrode is spaced from the high voltage source by a gap which is filled by the insulating fluid. 
     
     
       7. The instrument according to  claim 1 , wherein the at least one collector electrode is mounted directly to the high voltage source, or is mounted at a specified conformal offset from the high voltage source. 
     
     
       8. The instrument according to  claim 1 , wherein the insulating fluid is pressurised. 
     
     
       9. The instrument according to  claim 1 , wherein the at least one collector electrode is formed of conductive layers, semiconductive layers, and/or insulative layers. 
     
     
       10. The instrument according to  claim 1 , wherein the housing has an electrically insulative layer lining the inner surface thereof. 
     
     
       11. The instrument according to  claim 1 , wherein the housing has a passive or actively-controlled semiconductive layer lining its inner surface as a discharge control element. 
     
     
       12. The instrument according to  claim 1 , which is a well logging instrument. 
     
     
       13. A control system for controlling deionization in an instrument which produces ionizing radiation, the instrument including:
 a high voltage source of charge and ionizing radiation, 
 a housing filled with insulating fluid and containing the high voltage source; 
 an insulator to which the high voltage source is mounted so that the source is spaced from the housing, 
 at least one collector electrode arranged in the housing such that the high voltage source preferentially discharges to the at least one collector electrode, and 
 discharge rate limiting means; 
 wherein the control system is configured to: determine a level of ionization of the insulating fluid through an amount of discharge to the at least one collector electrode, and control the discharge rate limiting means to deionize the insulating fluid at a controlled discharge rate and thereby maintain a maximum rate of discharge below a predetermined current. 
 
     
     
       14. A method for controlling deionization including:
 providing an instrument which produces ionizing radiation, the instrument including a high voltage source of charge and ionizing radiation, a housing filled with insulating fluid and containing the high voltage source; an insulator to which the high voltage source is mounted so that the source is spaced from the housing, at least one collector electrode arranged in the housing such that the high voltage source preferentially discharges to the at least one collector electrode, and discharge rate limiting means; 
 determining a level of ionization of the insulating fluid through an amount of discharge to the at least one collector electrode; and 
 controlling the discharge rate limiting means to deionize the insulating fluid at a controlled discharge rate and thereby maintain a maximum rate of discharge below a predetermined current. 
 
     
     
       15. The method according to  claim 14 , wherein the discharge rate limiting means is further controlled to deionize the insulating fluid at a controlled location. 
     
     
       16. The method according to  claim 14 , wherein the discharge rate limiting means includes an electrical circuit which is controlled to vary an electrical bias applied to the at least one collector electrode relative to the high voltage source to encourage deionization of the insulating fluid at the at least one collector electrode. 
     
     
       17. The method according to  claim 14 , wherein the discharge rate limiting means includes a fluid circulator which is controlled to circulate the insulating fluid within the housing to preferentially encourage discharge of the insulating fluid at the at least one collector electrode. 
     
     
       18. The method according to  claim 14 , wherein the at least one collector electrode is spaced from the high voltage source by a gap which is filled by the insulating fluid. 
     
     
       19. The method according to  claim 14 , wherein the at least one collector electrode is mounted directly to the high voltage source, or is mounted at a specified conformal offset from the high voltage source. 
     
     
       20. The method according to  claim 14 , wherein the insulating fluid is pressurised.

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